1. Field of the Invention
The present invention generally relates to the testing of integrated circuit (IC) packages, and more particularly, the present invention relates to a test board for testing ball grid array (BGA) packages or micro ball grid array (μ-BGA) packages, and to a method of calibrating a tester for testing BGA or μ-BGA packages.
A claim of priority is made to Korean Patent Application No. 2002-79635, filed Dec. 13, 2002, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.
2. Description of the Related Art
Integrated circuits (ICs) and IC packages are analyzed for various characteristics, e.g., DC and AC characteristics, and/or tested for defects. To accomplish such analysis, a test board is used to electrically connect a main load board to a device under test (DUT), where the main load board is connected to automatic test equipment (ATE). In addition, as explained in more detail below, the test board is used in combination with a jig set during an ATE calibration process.
FIG. 1 illustrates a conventional test board used for testing a conventional “thin small outline package” (TSOP). Generally, TSOP's are packages which are not BGA or μ-BGA packages. As shown in FIG. 1, a test board 100 includes a printed circuit board (PCB: not shown) and sockets 10 mounted on the PCB. The sockets 10 have a plurality of contact terminals 20 for connection to the pins of a DUT (TSOP).
Prior to testing the DUT using the ATE, the ATE must first be calibrated to identify and compensate for measurement errors (such as timing errors) that may occur in channels of the ATE. Accordingly, a calibration apparatus is needed to measure such errors. For example, in a case where a TSOP is tested by a T559X series ADVANTEST® (which is an ATE made by ADVANTEST Corporation), errors in the T559X series ADVANTEST® are calibrated using a calibration robot.
In this case, referring again to FIG. 1, the contact terminals 20 of the sockets 10 into which the pins of the DUT are inserted are positioned at opposite sides of a region 30 in which probes of the calibration robot are positioned. Thus, for example, when the TSOP is tested by the T559X series ATE, an additional jig is necessary to electrically connect the probes of the calibration robot to the sockets 10 of the test board.
A well-known process of testing a TSOP using the T559X series ADVANTEST® ATE will be briefly described with reference to FIGS. 1 through 3.
FIG. 2 illustrates a jig set 200 used when calibrating an ATE using the test board shown in FIG. 1. The jig set 200 includes a PCB contact 210, a probing PCB 220, and a PCB guide template 230. FIG. 3 is a block diagram for explaining the calibration of an ATE using the jig set 200 shown in FIG. 2.
Referring to FIG. 3, an ATE 350 is connected to a main load board 320 via wire cables 351. The main load board 320 is connected to a test board 100 via wire cables 340. The test board 100 is supported by a supporter 330.
The PCB contact 210, the probing PCB 220, and the PCB guide template 230 of the jig set 200 (FIG. 2) are sequentially stacked on the test board 100. The PCB contact 210 electrically connects the sockets 10 (FIG. 1) mounted on the test board 100 to the probing PCB 220 via contact pins 31. The probing PCB 220 is for connection to probes 313 of an arm 311 of the calibration robot 310 via the probing points 30.
The PCB guide template 230 has holes 32 into which screws for fixing the PCB contact 210 and the probing PCB 220 onto the test board 100 are inserted.
When a calibration operation for calibrating the ATE 350 is performed, the jig set 200 components are mounted on the test board 100 as above, and then the arm 311 of the calibration robot 310 descends toward the probing PCB 220 to probe the probing points 30 of the probing PCB 220.
The calibration robot 310 receives test signals output from channels of the ATE 350 via the probes 313 of the arm 311 to measure characteristics (such as delay times) of a signal transmitted between the channels of the ATE 350 and the sockets 10 of the test board 100, and stores the measured data in a memory (not shown) of the ATE 350. The measured channels characteristics of the ATE 350 can vary depending on the characteristics of the wire cables 351 and 340 connected to the channels of the ATE 350.
After the ATE calibration process, when the DUT is tested by the ATE 350 (hereinafter referred to as a test operation), the components of the jig set 200 are detached from the test board 100 and the pins of the DUT are inserted into the sockets 10 on the test board 100.
The channels of the ATE 350 output test signals to the sockets 10 via the wire cables 340 and 351, and then the ATE 350 receives returned test signals via the sockets 10 and the wire cables 340 and 351. The ATE compensates for signal delay times in the received test signals using the data measured by the calibration robot 310.
As described above, the components of the jig set 200 must be attached to the test board 100 whenever the ATE 350 is calibrated, and then detached from the test board whenever the DUT is tested. Thus, time is disadvantageously expended during the attachment and detachment of the jig set 200.
Also, calibration errors, and thus DUT analysis errors, can arise when the components of the jig set 200 are not precisely attached onto the test board 100. Further, the number of jigs increases with an increase in the number of DUTs. Additional jigs increase overall costs, and it takes a significant amount of time to attach and detach a plurality of jigs onto and from the test board 100.